Starting with UNICOM Intelligence Data Model 5.5, the UNICOM Intelligence Data File CDSC supports a compressed file format. Compressed UNICOM Intelligence Data Files have a file extension of .dzf and are smaller and more portable than uncompressed (.ddf) files.

When you access data in a .dzf file, the UNICOM Intelligence Data File CDSC generates a corresponding .ddf file in the same directory. All operations are performed on the uncompressed .ddf file. If the .ddf file is changed, it is then automatically compressed into an updated .dzf file. Note that the uncompressed .ddf file generated by this process is not automatically deleted afterward. This is necessary for cases in which multiple applications access the same .ddf file concurrently. To save disk space, you can delete the .ddf file afterward.

If you do not have sufficient disk space for the uncompressed .ddf file, the UNICOM Intelligence Data File CDSC displays an error message. In addition, if a .dzf file is accessed and there is already a corresponding .ddf file with the same name in the same directory, the UNICOM Intelligence Data File CDSC does not generate a new .ddf file. All operations are performed on the existing .ddf file, which is then compressed into the updated .dzf file.

In rare cases, there may be a mismatch between a .dzf and .ddf file with the same name. For example, this can happen when a .dzf file is transferred to another user, modified, and then copied back to the directory that still contains an uncompressed .ddf file with the same name. In such cases, the UNICOM Intelligence Data File CDSC displays an error message. You must manually delete the outdated file to continue.